Cognitive Disorders & Cortical Syndromes

Understanding Cognitive Disorders

Cognitive disorders affect the brain’s ability to think, remember, reason, and function. These conditions can range from mild cognitive impairment to severe dementia, and they may be caused by neurodegenerative diseases, vascular conditions, infections, metabolic disorders, or other factors.

Early and accurate diagnosis is essential, as some causes of cognitive decline are treatable or reversible. Dr. Chetan Padghan provides systematic cognitive assessment and evidence-based management for cognitive disorders and cortical syndromes.

Types of Cognitive Disorders

Alzheimer’s Disease

The most common cause of dementia, accounting for 60–80% of cases:

• Progressive memory loss, especially for recent events
• Difficulty with language — word-finding problems, reduced fluency
• Impaired visuospatial abilities — getting lost, difficulty with complex tasks
• Changes in behavior and personality
• Loss of insight into one’s own deficits
• Gradual decline in ability to perform daily activities

Vascular Dementia

Cognitive decline resulting from cerebrovascular disease:

• Often follows strokes or is due to chronic small vessel disease
• May present with stepwise decline or gradual progression
• Executive dysfunction — difficulty with planning, organizing, and decision-making
• Gait disturbance and urinary symptoms may be prominent
• Risk factors include hypertension, diabetes, smoking, and atrial fibrillation

Frontotemporal Dementia (FTD)

A group of disorders caused by degeneration of the frontal and temporal lobes:

• Behavioral variant FTD — personality changes, disinhibition, apathy, loss of empathy, compulsive behaviors
• Primary progressive aphasia — progressive language difficulties (semantic, non-fluent, or logopenic variants)
• Typically affects younger individuals (40s–60s)
• Memory may be relatively preserved initially

Lewy Body Dementia (DLB)

• Fluctuating cognition — good days and bad days
• Visual hallucinations — vivid, well-formed
• Parkinsonian motor features — tremor, stiffness, slow movement
• REM sleep behavior disorder — acting out dreams
• Sensitivity to neuroleptic medications

Other Causes of Cognitive Decline

• Normal pressure hydrocephalus (NPH) — treatable triad of gait difficulty, cognitive decline, and urinary incontinence
• Metabolic causes — thyroid dysfunction, vitamin B12 deficiency, liver or kidney disease
• Infectious causes — HIV-associated cognitive disorder, neurosyphilis, Creutzfeldt–Jakob disease
• Autoimmune encephalitis — treatable immune-mediated cognitive decline
• Depression-related cognitive impairment (“pseudodementia”)
• Medication-related cognitive effects
• Chronic subdural hematoma — treatable cause of cognitive decline in the elderly

Mild Cognitive Impairment (MCI)

• Cognitive decline greater than expected for age but not meeting criteria for dementia
• May involve memory (amnestic MCI) or other cognitive domains
• Increased risk of progression to dementia
• Important window for intervention and monitoring

Cortical Syndromes

Aphasia

Impairment of language function:

• Broca’s aphasia — difficulty producing speech, non-fluent, preserved comprehension
• Wernicke’s aphasia — fluent but meaningless speech, impaired comprehension
• Global aphasia — severe impairment of both expression and comprehension
• Primary progressive aphasia — gradual worsening of language abilities

Apraxia

Inability to perform learned motor tasks despite intact motor function:

• Ideomotor apraxia — inability to perform gestures on command
• Ideational apraxia — inability to sequence complex actions
• Speech apraxia — difficulty coordinating speech movements

Agnosia

Inability to recognize objects, faces, or sounds despite intact sensory function:

• Visual agnosia — inability to recognize objects by sight
• Prosopagnosia — inability to recognize familiar faces
• Auditory agnosia — inability to recognize sounds

Other Cortical Syndromes

• Neglect syndrome — inattention to one side of space
• Acalculia — impaired ability to perform calculations
• Alexia — impaired reading ability
• Agraphia — impaired writing ability

Diagnostic Approach

Cognitive Assessment

• Detailed history from patient and family/caregivers
• Screening tools — Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA)
• Detailed cognitive domain testing — memory, attention, language, executive function, visuospatial abilities
• Behavioral and functional assessment
• Neuropsychological testing for comprehensive evaluation

Investigations

• Brain MRI — to assess brain structure, atrophy patterns, vascular changes, and rule out treatable causes
• Blood investigations — thyroid function, vitamin B12, folate, calcium, liver and kidney function, syphilis serology, HIV testing
• EEG — for certain conditions (Creutzfeldt–Jakob disease, autoimmune encephalitis)
• CSF analysis — when indicated (infections, autoimmune conditions, neurodegenerative biomarkers)
• PET scan — FDG-PET or amyloid PET in selected cases

Treatment Approach

Reversible Causes

• Treating the underlying condition — thyroid replacement, vitamin B12 supplementation, shunting for NPH, treating depression
• Medication review — discontinuing or adjusting medications that impair cognition

Alzheimer’s Disease

• Cholinesterase inhibitors — donepezil, rivastigmine, galantamine
• Memantine — for moderate to severe Alzheimer’s disease
• Behavioral management strategies
• Caregiver education and support

Other Dementias

• Condition-specific management where available
• Symptomatic treatment for behavioral and psychological symptoms
• Non-pharmacological approaches — cognitive stimulation, structured routines, environmental modifications

Supportive Care

• Speech therapy for aphasia and swallowing difficulties
• Occupational therapy for maintaining daily living skills
• Physiotherapy for mobility and fall prevention
• Safety planning — driving assessment, home safety modifications
• Advance care planning and legal considerations
• Caregiver support — education, respite care, support groups

When to Consult a Neurologist

• Progressive memory loss affecting daily functioning
• Difficulty finding words or understanding conversations
• Changes in personality, behavior, or judgment
• Getting lost in familiar places
• Difficulty with complex tasks that were previously easy
• Rapid cognitive decline over weeks to months
• Cognitive changes associated with movement problems or hallucinations

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Dr. Chetan Padghan provides systematic cognitive evaluation and dementia care in Pune. If you or a loved one is experiencing memory problems or cognitive changes, early evaluation can make a significant difference. Schedule a consultation today.